session_set_save_handler

Right now the only way to change the serialize_handler is through php.ini or ini_set. Would it not make sense to have this part of session_set_save_hanlder and allow people to register there own functions or even no function at all for this? One usefull example of this, someone using a database to session information might want to store and update session variables 1 at a time to reduce the amount of data passed around in large sessions. At this time the only way to do that is to unserialize the data on writes and serialize the data on reads manually.